'Bond servant' in the Bible

The Revelation of Jesus Christ, which God gave Him to show to His bond-servants, the things which must soon take place; and He sent and communicated it by His angel to His bond-servant John,

And they *sang the song of Moses, the bond-servant of God, and the song of the Lamb, saying,“Great and marvelous are Your works,O Lord God, the Almighty;Righteous and true are Your ways,King of the nations!